P05FFBrake Pressure Sensor/Brake Pedal Position Sensor Correlation
- Generic OBD-II code · Powertrain
- How the car detects it
- Stop-start decides when to stop and restart the engine from the brake: Ford stops it when the pedal switch is on and master cylinder pressure is high enough, and restarts when pressure falls below a filtered reference. P05FF means brake pressure (from the sensor in the ABS unit, sent over the network) and brake pedal position do not agree – for example pedal pressed without pressure build-up, or pressure without pedal. Ford's 2020–23 petrol vehicles check this continuously in the section 'Brake Diagnostics for Stop-Start Dependability' and set the code within 1 s, without the check engine light; stop-start is blocked so the engine is not stopped or started unexpectedly. Ford gives no threshold for the deviation. GM monitors the pedal travel sensor under P057x instead. Brake switch disagreement is P0504.
- What you may notice
- Stop-start disabled
- No check engine light at Ford, possibly wrench or service warning
- Possible related codes P0504 or brake pressure codes
- Likely causes
- LikelyBrake pedal position sensor or switch misadjusted or faulty
- PossibleMaster cylinder pressure sensor in the ABS unit faulty
- PossibleNetwork communication or software between ABS module and engine module
- RareAir in the brake system or hydraulic fault (long pedal travel without pressure)
- Repair
- Hard · Usually a job for a workshop.Typical cost: €80 – €1,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.